The feasibility of conducting a longitudinal analysis of the development of predatory attack elicited by electrical stimulation of the brain in kittens will be investigated. To overcome the problem of displacement of the electrode during growth of the brain, two techniques are proposed: (1) use of the threaded moveable electrode which can be lowered deeper into the brain, and (2) implantation of several hollow guide tubes thru which additional electrodes can be lowered into the neutral substrate when the initial electrode is displaced. In evaluating these techniques, the functional status of the neural substrate for predatory attack throughout ontogeny will be determined by daily stimulation tests.